Schwannoma

Gene: LZTR1

Green List (high evidence)

15 different germline heterozygous mutations in the LZTR1 gene identified in 16/20 probands with schwannomatosis. There were 6 truncating mutations, 1 in-frame splice site mutation, 1 deletion affecting a splice site, and 7 missense mutations at highly conserved residues. Mutations segregated with disease in all available affected first-degree relatives, although four asymptomatic parents also carried an LZTR1 mutation.

All schwannomas studied also carried the heterozygous LZTR1 mutation, and all showed loss of heterozygosity (LOH) at chromosome 22q11, including the LZTR1, NF2, and SMARCB1 genes. In addition, all tumours carried a heterozygous somatic mutation in the NF2 gene. These findings were consistent with biallelic loss of function of both LZTR1 and NF2 in all tumours. Functional studies of the variants were not performed. Pathogenesis of tumour characterised as resulting from 3 mutational events: a germline LZTR1 mutation (E1), a deletion of 22q that includes the LZTR1 and NF2 genes (E2), and a somatic NF2 mutation (E3). Loss of LZTR1 function can predispose to the development of autosomal dominant multiple schwannomas, thus implicating LZTR1 as a tumor suppressor gene.
Sources: Expert list, Expert Review

Created: 12 Sep 2024, 1:39 a.m.

Mode of inheritance
MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted

Phenotypes
Schwannoma, MONDO:0002546; Schwannomatosis 2, MONDO:0014299; Schwannomatosis, susceptibility to, 2, MIM#615670

Publications

• PMID: 24362817, 29517885

Variants in this GENE are reported as part of current diagnostic practice